This story is produced in partnership with Racquet magazine and appears in issue no. 7.

Losers are a fixture of my workday as a sportswriter.

Talking to a person coming off court who was just dealt a crushing defeat, and offering some vague, platitudinous comfort to assuage their raw battle wound, is a necessary task in the job. On rarer occasions, I’ve talked to those who have just suffered a defeat so harrowing and derailing that it has them visibly doubting the viability of their career. But for most losers, even in down moments, there’s the credibility and dignity of having just performed for an appreciative crowd of some size in a respected, aspirational pursuit like professional sports.

There’s nothing remotely aspirational, though, about the Applebee’s restaurant I found myself in during day 6 of the 2017 US Open. And sitting across a table bearing mozzarella sticks and glasses of tap water, these were not my normal losers.

Rainer Piirimets, a three-year veteran of the tennis tour from Estonia, was knocked out of the US Open the day before, exiting Arthur Ashe Stadium in the early afternoon. His partner, a fellow Estonian who has been on tour for 10 years, sat beside him.

Piirimets left the stadium not through the tunnel to the locker room, but out a side gate. His wrists bore no sweatbands, only handcuffs.

The request for this interview was not made, as most I do, through the tournament media desk, but rather through a Facebook message. Piirimets eagerly accepted. Meeting at Applebee’s was his suggestion, but he wasn’t hungry—just eager to set the story straight after spending 10 hours in police custody the day before.

“We’re not criminals,” Piirimets said, a phrase he and his friend would use as a refrain over the next two hours.

Piirimets had sure been treated like a criminal the day before. While watching the third-round match between Petra Kvitova and Caroline Garcia, he was spotted in his seat in the upper deck (Section 331) by tournament security officials and escorted out. He was then arrested in a small room just off the concourse by police, who then perp-walked him out of the stadium. The cops steered him through a dense crowd of staring, perplexed tennis fans and ducked him into a waiting police car outside the tournament gates.

Piirimets, a competitive high jumper in his youth, was then put in a jail cell at the 110th Precinct in Queens, which he shared with, he said, an agitated, profane homeless man. After several hours in the lockup, he was brought to a court for arraignment before a judge. He was then released and given a summons to appear in court again seven weeks later. He doesn’t plan on attending.

His friend, who I’ll call Pete, was equally animated about the treatment Piirimets had received.

“To keep him for 10 hours in prison, for doing what?” said Pete. “He made a little mistake, no big deal.”

His crime was trespassing. Piirimets had also been kicked out of the US Open the year before, and during that first ouster he was given paperwork acknowledging that he was to be banned from the tournament grounds for 20 years. He said he didn’t think that threat was serious, and that he didn’t think he was bound by the forms because he didn’t sign the line at the bottom. Nor did he understand that trespassing was a crime that could get him arrested in the United States. After all, he said, he’s been kicked out of lots of tournaments, all over the world, and nothing like this has ever happened before. Because why would it? He’s not a criminal, he said, flummoxed.

What Piirimets is, he admitted, is a member of a rogue, impish species in the tennis ecosystem: a courtsider. But with their hunters getting more and more adept, courtsiders—arguably justifiably so—have become an endangered species. Only the most stubborn of their breed persist. Even though sports betting is becoming legalized in the United States, they will still be persona non grata at this year’s US Open, which they will attempt to attend again.

Though only the second courtsider ever arrested at a Grand Slam event, Piirimets was the eighth caught in the first five days of the 2017 US Open, according to the USTA—which prides itself on “vigorously combatting” courtsiding and was quite excited to alert the media to his arrest. Twenty courtsiders—17 men and three women (none American)—had been caught during the 2016 tournament, hailing from as far away as Sri Lanka, each thinking they had the skills to beat the system. All were given notice of a 20-year ban from the tournament.

* * *

To work as a courtsider is to have possibly the most exotic, adrenaline-pumping data-entry job imaginable.

Put simply: Courtsiding is the practice of independently transmitting information from a tennis match for a purpose related to gambling.

Odds fluctuate constantly during a match, with each point causing some movement—odds usually shift massively after a break point in a men’s match, for example. For high-tech, computer-assisted gambling outfits, whoever knows the result of the point most quickly will know which way the odds are going to move before the market can react and, if they act fast, can take advantage of the (barely) outdated odds for profit.

Most professional gamblers do not rely on hunches or instincts; the most advanced use sophisticated algorithms to predict the chances each player has of winning the match. When fresh data about who has won each successive point arrives from the courtsider, the algorithm computes the new probabilities and wagers are adjusted accordingly.

Accepting a risk of possible losses is mandatory for any gambler, but the opportunity in tennis makes it irresistible for many professional gamblers. For even unremarkable tour matches between lesser-known players, millions of dollars are routinely wagered. Tennis is an extremely attractive sport for gamblers: There are matches, somewhere in the world, being played constantly at all hours of the day. There is always a winner—no draws—and there is a steady stream of data to analyze and process to compute probabilities, unlike, say, soccer, where there may be only a small handful of decisive moments in a 90-minute game.

Because it has the highest volume of betting and most steady progression of scoring, tennis attracts the highest incidence of courtsiding, but it is also found in other racquet sports, and occasionally in other sports like cricket and basketball.

To work as a courtsider is to have possibly the most exotic, adrenaline-pumping data-entry job imaginable.

Courtsiders generally purchase tickets to the tournament and sit in the stands among fans. They are not usually directly placing the bets themselves. Typically, a courtsider will push a button on their phone as soon as a point is won, which sends that information to a person manning a computer at a base elsewhere, who then updates the live in-match bets, making the courtsider essentially a field operative reporting to mission control. The information is used to bet on not the winner of that specific point, but the winner of the entire match.

All of it is for marginal gain, but time is money. If a courtsider can consistently be fast—while being accurate—they will reap a higher rate of success for their teams in their gambling.

While their task is simple, like in any craft, courtsiders gain acuity and skill with practice. The job requires focus and precision, as well as energy, endurance, and an ability to rise above crushing monotony. Enjoying tennis at least somewhat is a prerequisite, but even the biggest fans can be numbed by having to pay unflinching attention to unappealing, hours-long matches.

Like fans, courtsiders have favorite players, judged for both entertainment and work purposes. Pete said it was advantageous for him to be courtsiding on big, flat hitters like Juan Martin del Potro or Petra Kvitova, who tend to miss wildly when they misfire. When one of their balls starts sailing way out, he can hit the preassigned button on his phone before it even lands. Players who use a lot of topspin are trickier; a looping Rafael Nadal forehand might seem like it’s flying way long, only to dive back into the court just inside the baseline.

Some courtsiders take bigger risks than others when it comes to updating a score while the ball is still in play. It can be tempting to confidently enter the score when a player is positioned for what looks like an easy put-away winner, but even the simplest-looking shot can prove precarious, as any tennis player at skill level knows well.

A courtsider’s mistake can be costly. Just one incorrect update of the winner of a point will throw off the algorithm enough to prove disruptive. A worse pitfall is inattention to other decisive factors in the match, specifically an ailing player. If a courtsider notices that a player is hurt or has called a medical time-out, they are supposed to report that back to the base as quickly as possible, so that betting on that player can be suspended.

Pete said his heaviest loss came during a match at Paris-Bercy in 2011, when he didn’t notice that Mardy Fish was struggling with an ankle injury.

“I didn’t see the doctor coming out,” Pete lamented. “It all went sideways.”

Pete is reluctant to divulge any information about how much money they are betting or earning, but said that one Mardy Fish match cost his team $15,000. But compared with other higher-stakes outfits, he said, the members his team are “not big fish.”

That same year, a fellow courtsider, Aussie Brad Hutchins, became distracted by a friend bringing him a pulled pork sandwich during a changeover in Miami and didn’t notice heavily favored Andy Roddick receiving a medical time-out. While he wolfed down lunch, the rest of the market reacted quickly and started betting heavily on Roddick’s opponent, Pablo Cuevas. Play continued, but Roddick lost the match, and Hutchins’ momentary distraction caused major losses. In the end, that pulled pork sandwich cost more than $32,000.

* * *

Several months later, I caught up with Hutchins, who quit courtsiding years ago and is much happier as a result.

The impression Brad Hutchins makes as he sips a long black at a cozy Thai coffee shop in Brisbane’s trendy West End neighborhood couldn’t be further from the downtrodden Estonians at that Applebee’s. He’s tan and smiling brightly, recently back from a snowboarding trip in the Alps and stylish with a tight black T-shirt and Dolce & Gabbana sunglasses. If the courtsiding industry ever needed a poster boy, it would be him.

Hutchins already has a more public profile than most in his trade. In 2014 he published the book Game, Set, Cash!, a memoir about his two years traveling the tour as a courtsider. Though Hutchins details the lows of the job—particularly harrowing encounters with sadistic security officials in less-developed countries—the highs make the whole ride seem worthwhile. His book is a romp-around-the-world filled with adventure, friendship, booze, and sex—all improbably made possible by merely sitting at a tennis court with a phone in his hand.

The perks were great—he had a company credit card that covered all expenses—and when it went well, his job satisfaction was considerable.

“It’s beating the system, and that feels good,” he told me. “It’s fun, because you’re beating the big guys with all the money.”

Hutchins writes of one particularly inept spotter who worked the tournaments in California. “I trade one set from my pocket while standing next to him for a laugh,” he writes. “I am so relaxed I even have the nerve to take a photograph of the ignorant scout while he searches the stands with his binoculars.”

Unlike the Estonians, who struggled to categorize their work beyond saying that they were “not criminals,” Hutchins quickly articulated an impressive description of the courtsiding trade that put it in a league with disruptive, groundbreaking business models like Uber or Airbnb.

“I think that the top guys who are doing it are entrepreneurs,” he said. “They’ve figured out a market that nobody else really knows exists. They’re exploiting a market in a way that is definitely taking advantage of something they discovered. They’re businessmen, really. But we’re also doing something in an area that’s new, and pushing the boundaries of what people can do.

“You’re discovering new territory, and when you’re doing that there’s always going to be a negative reaction toward that until people understand exactly what it is that you’re doing. That’s half the problem: It’s undefined. So they’re asking, ‘Are you involved in match fixing? Are you just sending off scores? What are you doing?’ Because it’s such a new thing, and most of the public don’t know what it is, I think half the problem that exists is the ambiguity of it.”

They’ve figured out a market that nobody else really knows exists. They’re exploiting a market in a way that is definitely taking advantage of something they discovered.

Hutchins said the landscape shifted dramatically between his first and second years on tour, after the first tennis data rights deal was signed. Though he remained adamant that he was doing nothing wrong, the scorn and constant setbacks took their toll.

“It was very frustrating,” Hutchins said. “You see people’s reactions next to you, saying, ‘Who the hell is that guy, what has he done? He’s a quiet guy who’s just been sitting there, why is he getting dragged off?’ You get a thick skin to it after a while and just kind of block it out. But at the same time, you get frustrated because you can’t work. It’s not being allowed to do your job, someone saying you’re not allowed to work today for no real reason, other than that we’ve decided that we want to make money, and you can’t.”

A lifelong tennis fan, Hutchins took particular sadness at being banned for life from Wimbledon, which he said was by far the most effective of any tournament at catching courtsiders nearly instantly.

(A Wimbledon spokeswoman said in a statement that the All-England Lawn Tennis Club is “committed to achieving the ‘gold standard’ of measures to protect the integrity of The Championships,” including courtsiders. “The AELTC works closely with the relevant authorities to deal swiftly with any instances of courtsiding detected,” she said.)

With the shine worn off from the job, Hutchins gave it up for good in 2013.

“I think I’d had my fun, to be honest,” he said. “I’d traveled for years on the road, and it was nice to actually come home, relax, and to have a normal life, yeah.”

When he published his book about his time on tour a year later, he didn’t worry that he was giving away the tricks of the trade, or possibly handing the courtsiders’ playbook to the other side.

“I ran it by a fair few people first, and they said, ‘Awesome, go ahead—whatever, it’s a dying trade now anyway,’” he said. “I didn’t feel like I was throwing anyone under the bus, because we knew that it was done and dusted. We knew that those golden days were over. I wasn’t ruining anyone’s party, it was already done.”

Hutchins now teaches at a primary school in Gold Coast. He acknowledged that much of his book is “not really appropriate” for the curious students, but he occasionally spices up math lessons on probability with examples from his time in tennis.

Sometimes a friend at a party will ask him to explain his past life to impress someone new. Courtsiding was a fun ride, but it’s a complicated one to explain. “It’s never a short conversation,” he said.

His new, more stable life has advantages: His line of work is accepted and conventional, and he can have a steady girlfriend. But after the rush of courtsiding, he admitted it has been difficult to shift gears into a slower-paced life.

“The grass is always greener,” he said. “Once you’re in the grind of working in a normal, repetitive job, you go a bit stir-crazy and just want to get out. I still travel quite a bit, but it’s nice when somebody else is picking up the bill and you can have free rein. The more time goes on, the more I appreciate it and realize that it’s probably going to have been the best years of my life, for sure. The memories I’ve got from it are awesome.”

Filling the void hasn’t been easy.

“It was really frustrating for me going back to a quiet, mundane life,” he said. “Luckily for me I’ve got surfing, and I surf every day and I love that. I need some sort of passion in my life, so I do that.”

When he needs more of an adrenaline rush, he can find bigger waves in Indonesia. The snowboarding trip he just returned from also offered tantalizing danger.

“The avalanche risk just then in the French Alps was out of control,” he said, palpable excitement in his voice. “They had three meters of snow in the two weeks we were there; they got hit by this huge storm, and we had to wear beacons and carry shovels in case anyone got buried. I’ve always enjoyed those adrenaline sports, I love it. So I’ve got that, which is great.”

* * *

Though conducted on the margins of legitimacy, courtsiding is by no means the only field that takes advantage of incremental edges sought in traditional exchanges. High-frequency traders on the stock market have bought properties as close as possible to the stock exchange to minimize the milliseconds it takes for a transaction to be sent to the exchange’s servers. Traders have also obsessed over laying the straightest possible fiber-optic cable between computers, even over long distances, such as one between Chicago and New Jersey that author Michael Lewis said was ordered to be “the most insistently straight path ever dug into the earth.”

In stock trading this is called front-running, and it results in constant high-volume, low-risk yields. And while it creates a technological arms race in finance that ultimately squeezes out lower-volume investors, it’s not illegal.

But while a stock market’s data is open for anyone to transact with as best they can, tennis authorities want to make their market closed.

“I don’t agree [that courtsiders] have a right to use the data,” Bill Babcock, director of the Grand Slam committee, told The New York Times in 2014. “Scoring is the right of the tournament.”

That possessiveness would be unlikely to hold up in any court, however: Judges around the world have consistently ruled that the statistics generated by a sporting event do not qualify as intellectual property. In fact, even the companies that own data rights in a sport, such as Sportradar, also offer their services as third-party stats providers for other leagues in which they have bought no official stake.

Piirimets incredulously illustrated how ridiculous he believes it is to restrict spectators from sharing information about the match they’re watching: “You can’t send your grandfather a message to say ‘Nadal’s leading now, 2–1’? How’s that?”

His hypothetical obfuscates the purpose of courtsiding, but the larger point is valid: How can a tennis tournament restrict the conveying of nonconfidential information, such as the score of a match?

Data rights are somewhat analogous to broadcast rights, which are a more widely understood market. Both license the outflow of live information from a sporting event for profit.

There are significant differences, however. The ATP and WTA tours told FiveThirtyEight that they’d spent $10 million on infrastructure for data distribution, a sum that would pale in comparison with their spending on television broadcasts. Assembling and producing a broadcast has considerable base costs—cameras, microphones, commentators, technicians, directors, statisticians, graphics—but the transmission of data requires scant hardware or personnel.

The on-court setup is minimal—just a tablet screen to tap after each point—and that task is performed by a person who was already on court: the chair umpire. Chair umpires tap in which player won the point, as well as limited statistical information: missed first serves, aces, and double faults. That information is sent not only to the electronic scoreboards around the court or stadium, but around the world, for use by sports-news websites and betting companies.

When the rights to this chair-umpire-created data were first commoditized and sold in 2011, it was found money for the tours—and bushels of it. The rights have been scooped up by two companies: IMG, which owns rights to the WTA Tour, the ATP World Tour, the ATP Challenger Tour, the French Open, Wimbledon, and the US Open; and Sportradar, which owns the Australian Open and ITF events such as Davis Cup and Fed Cup.

Though the creation of the data is simple, access to it doesn’t come cheap: Even the data rights for the lowest level of professional tennis, the ITF Pro Circuit events known as Futures, have been reported to have been sold to Sportradar for between $12 million and $14 million per year. However insane those numbers may seem, the value of the data will only rise now that sports betting is being legalized in the United States.

IMG and Sportradar maintain the quality and uniformity of the data and then sell it to both media companies and betting companies (and sometimes fantasy-sports companies, which are seen as something of a middle ground).

Betting outfits that use courtsiders trust that their independent data will be faster and better than the available official product. And when it is, they profit.

* * *

A tennis tournament’s hostility toward courtsiding is similar to a casino’s hostility toward counting cards at a blackjack table: Neither activity violates any laws, but if the management frowns upon it they can make it cause for removal.

Whether they could justify it in a court or not, tennis tournaments are private entities that reserve the right to remove anyone for any reason. The small print of tickets contains a provision that prohibits the dissemination of data by any attendee; posted signs around a tournament often state similar restrictions.

Courtsiders initially fell under the jurisdiction of the Tennis Integrity Unit (TIU), a watchdog group supported by the governing bodies of the sport that is “responsible for enforcing the sport’s zero-tolerance policy on betting-related corruption.” Though it seems a stretch to consider their behavior “corrupt,” courtsiders were made a part of the TIU’s scope.

A tennis tournament’s hostility toward courtsiding is similar to a casino’s hostility toward counting cards at a blackjack table: Neither activity violates any laws, but if the management frowns upon it they can make it cause for removal.

Since it requires clear, determined contravention of rules set in place by tournaments, the TIU paints courtsiding as a possible gateway activity toward more serious rule-breaking.

“The starting point is that TIU regard courtsiding as a potential threat to the integrity of the sport,” said Mark Harrison, a spokesman for the TIU. “In all cases, courtsiding breaches the terms and conditions of entry to professional tennis events, which prohibit the sending of live scoring data from a venue to third parties for gambling purposes. Over and above those concerns, TIU believe there is the potential for individuals to seek further advantage by obtaining inside information or other data that is not available to the general public, which could assist gambling.”

Though it defers to the security personnel of each individual tournament to spot and eject courtsiders at work, TIU maintains a list of persons who are prohibited from receiving credentials at tournaments, which includes known courtsiders (among other methods, courtsiders have been known to successfully pose as journalists and obtain media credentials).

The courtsiders I’ve spoken to vehemently denied that their work has anything to do with corruption or match fixing, and consider the notion of it being on a slippery slope toward match fixing laughable. In fact, the courtsiders said, a fixed match can be catastrophic for them. Their betting algorithms follow precalculated probabilities, and so a player who performs in an unexpected, untoward way can wreak havoc on their system.

In rare cases, a suspected fix can sideline a courtsider completely. In the week before the US Open, Pete had been in Winston-Salem, ready to courtside on a first-round match between Alexandr Dolgopolov and Thiago Monteiro. But when questionable volumes of cash began to pour in on Monteiro, leading to suspicions that Dolgopolov was going to tank the match, betting markets suspended trading on the match, leaving Pete annoyed and marooned purposelessly in the stands (Dolgopolov, who has been previously associated with suspected fixed matches, indeed lost the match, but denied any fix).

It’s possible a courtsider could work in concert with a match fixer, but there would be little additional edge to courtsiding a match of which the outcome is predestined. Further, it’s also unlikely that match fixers, who can successfully puppeteer a match from anywhere on the globe, would ever risk sending someone to the scene of the crime, so to speak. No courtsider has ever been charged with trying to influence the outcome of a match, or any other corruption offense.

The tangle of data rights and integrity issues was further complicated by recommendations made in April by the Independent Review of Integrity in Tennis, which had been commissioned by tennis’ governing bodies. One of the panel’s main recommendations was for the data deals with Sportradar to end. This would only, most likely, saturate the lower tournaments with courtsiders, who would now have complete domain over data from those events.

TIU’s remit strictly sticks to rooting out corruption that affects what happens on court; it is not responsible for preserving the exclusivity of data rights. But tournaments, which have made millions selling their data, bristle at anyone who could potentially threaten that revenue stream.

Tournaments intensified their fight against courtsiders in 2012, the first season in which the rights deals kicked in, hiring outside firms to protect their new cash cows.

“It was clear as day, you could see the change,” one courtsider said of the difference in the beginning of the 2012 season. “The message they must send to security is that these guys are match fixers, or doing something illegal. Because security, like, hated us, and they’d look at us like we’re scum.

“And you’d think to yourself: ‘What have they told you for you to be acting this way towards me? You don’t know me, and you’re making assumptions.’ That wasn’t nice, being looked at like that by people on a regular basis,” said Brad Hutchins, the retired courtsider. “It would become that every Monday you were dragged off the court again, and just looked at in a really disdainful way. You knew that you weren’t doing anything illegal, and yet these people would act as if you were.”

That demonization, and justifying harsh treatment of courtsiders by equating them to match fixers, was present not just in the men who physically pulled courtsiders out of stadia, but also in the sport’s executives, who created a small-scale moral panic around the little-understood practice in their comments to media.

David Brewer, the US Open tournament director, has said that a connection between match fixing and courtsiding “would certainly seem to be a logical conclusion that some people could reach.”

“Where there’s smoke, there’s fire,” he said.

Craig Tiley, the Australian Open tournament director, told Reuters that he viewed courtsiders as a threat to the sport’s integrity.

“Yes, they’re not affecting the match, they’re not affecting the outcome or the score, but they are utilizing a small opportunity that exists in the sport to gain a benefit out of it that arguably could be illegal, maybe some cases legal,” Tiley said. “My view is that what they’re doing is pushing the boundaries of what you would consider to be acceptable in integrity, relative to the sport.”

Tiley’s comments came after a courtsider was arrested at his tournament in 2014. Daniel Dobson, a 22-year-old Englishman, was arrested with great fanfare and charged under a new law that prohibited trespassing, like Piirimets, but with “engaging in conduct to corrupt a betting outcome.”

Graham Ashton, a deputy commissioner with the Victoria Police, said that courtsiding was “a type of cheating” on a slippery slope likely to lead to worse offenses.

“Courtsiding is really only one step away from then contacting players and getting engaged in more illicit and sinister types of sports corruption,” Ashton said.

Dobson faced up to 10 years in prison under the new law. But once he was in custody, he quickly realized that the police officers who were questioning him didn’t have a basic understanding of what his job actually entailed.

“They thought I was having an impact on the integrity of the sport, having contact with the players, corrupting the sport in some way,” he told the BBC. “But the truth is, that’s not what courtsiding is.”

Dobson worked for a British betting outfit called Sporting Data, which employed six courtsiders as part of its data-gathering operation. Though the charges against Dobson were dropped, the negative publicity around his arrest caused the company to suspend its courtsiding operations.

Most other courtsiders have stopped as well, frustrated by getting caught more frequently. In 2014, then WTA chief executive Stacey Allaster addressed courtsiding as a past-tense issue, telling SportsBusiness Journal that it was “not as big a problem anymore because word has gotten out that tennis is vigorously protecting its live scoring rights.”

Not everyone had surrendered to the prevailing tide, however. Including the two men across from me at Applebee’s.

* * *

Courtsiding offers an incredible international adventure for its craftsmen, and it’s taken Piirimets and Pete around the world. I pulled up the 2017 tour calendar on my phone, curious how much of the tour they had visited compared with my own fairly extensive travel to cover the sport.

Their itineraries dwarfed mine. Nearly every city I read off the schedule was answered in the affirmative. They had been to every tournament in Australia and the United States, and nearly all in Europe. Between the two of them, they had been to over 50 tournaments, and that’s not even counting the smaller Challenger-level events.

Several tournaments triggered memories. Piirimets laughed when I asked about a new WTA tournament in Biel, Switzerland. He went, but it was so small and underattended that he was detected and ejected within the first hour. In Rome, he had once been kicked out within a few steps of entering through the turnstiles, before he even reached a court. Pete had a similar experience at the World Tour Finals in London, being spotted on a staircase before he’d even made it to his seat. Indoor tournaments, they agreed, were more difficult: fewer courts, and fewer places to hide.

There were a few surprise omissions: They had never been to Stockholm, near Estonia, because other tournaments that week were in cheaper cities. Nor had they ever been to Wimbledon, because it was too difficult to get tickets—and because it falls during Estonia’s major summer festivals.

While competitive with one another in theory, the courtsiders are generally a very social group wherever their paths cross around the world. The young men who make up the majority of the workforce split hotel rooms and merrily carouse whenever possible, wherever the tour may have taken them that week, walking back into the tournament the next morning blissfully hungover.

Though they allude to brighter times, it’s hard to sense any joy in this craft on this afternoon in Queens, as our mozzarella sticks congeal. Instead of talking about friends they’ve made along the way, they talk obsessively about their enemies: the spotters.

Spotters are a small, dedicated group of contracted employees whose sole responsibility at tournaments is identifying courtsiders. Once they spot a courtsider, they report the find to tournament security. The security staff is local to each tournament, and the levels of politeness or cruelty with which they handle the task vary widely.

Though the courtsiders usually just come in direct contact with these temporary employees, it’s the spotters traveling the tour in parallel who become their recurring archrivals.

Pete is especially fixated on Dany Kalombo, a former line judge and chair umpire from France who is also a leading spotter, Pete said, and a foil who seems to be outsmarting them at every turn. Always sharply dressed and bespectacled, Kalombo is the closest thing tennis has to a Hercule Poirot.

“Dany’s really sharp,” Pete said, almost reverently. “He knows exactly when to go look for someone, and when not. He knows where the market is, and where there’s money, and where there’s not money. He knows everything. That’s why he’s quite a tough cookie for us. He gets inside information—and we’re quite interested in where he gets this information from.”

Kalombo’s LinkedIn page says he currently works as an independent contractor for Data Controller Licencing, which “has been carefully designed to fight back against data dissemination by unapproved third parties, to protect the data rights that are owned by the Tour.”

As “shadowy” as courtsiding is—to use the word most often used in news articles about the phenomenon—the opposition keeps itself more obscured. No other information could be found anywhere online about DCL outside of Kalombo’s LinkedIn page. Kalombo declined an interview request and directed questions to the ATP, which also declined to reveal any operational details—as did every other tennis organization covered.

Pete has learned some of their patterns, though. He knows they know to focus on matches that will have the highest betting volume; at Challengers, for example, they usually don’t show up until the third day of the tournament.

Pete also said that many of the spotters are family members of chair umpires.

“Everyone’s getting rich, all the siblings,” he said. “‘You’ve got nothing to do? Come to the tennis, be a spotter. We’ll give you $1,500 a week—and you don’t have to do much. If you don’t catch anyone, don’t worry, you’ll get someone next week.’ They just go around, week after week, $1,500 a week. It’s not big money, but with no strings attached, it’s pretty good. I would take that job.”

Piirimets said that because they don’t believe the spotters get bonuses for catching courtsiders, he gets frustrated when they kick him out upon first seeing him.

“Why can’t we play more cat and mouse?” he said. “Come on, you can’t just give me until tomorrow, and then kick me out then?”

This sense that there should be a symbiotic relationship is part of why Piirimets is so mad. Spotters had kicked him out of the WTA tournament in New Haven the week before, and they told him that they’d see him next week in New York. They should have warned him, he said, that an arrest was looming because of the trespassing laws there.

‘Why can’t we play more cat and mouse? Come on, you can’t just give me until tomorrow, and then kick me out then?’

In its earliest days, before any crackdown began, the first courtsiders were able to openly and directly place bets themselves from their laptops in the stands. Once courtsiding was declared verboten, that became too obvious, so most switched to the stealthier method of tapping the updates into a phone, often held by their side, in their lap, or in a pocket. Usually the equipment is rudimentary—just a simple cellular phone, often a Nokia, and a bunch of battery packs to last the entire day. In rarer cases, some MacGyverish courtsiders push buttons connected to wires that have been sewn into an article of clothing, or even speak the scores aloud into a small microphone to be heard by a person on the other end of a telephone call.

According to legend, once at the Australian Open, a courtsider at a women’s match was tapping his phone underneath a towel in his lap. Security approached him with a more disturbing type of disdain than usual: Several spectators had suspected him of masturbating to the players on court.

“Enjoy getting your rocks off to women’s tennis, huh?” the security guard said. Somewhat bafflingly, the man thought it would be as bad to admit to courtsiding, so he accepted the charge, paid a $560 fine, and was given a 24-hour ban from the grounds. In the end, being an admitted public masturbator resulted in a far shorter ban than being an admitted courtsider, which would have kept him out for the rest of the tournament.

Occasionally, aggressive spotters brusquely confront baffled spectators—perhaps a journalist with a laptop or a fan tapping on an iPad. The tours would not disclose what percentage of their approaches are made to uninvolved parties.

Some known courtsiders wear wigs or masks or other disguises, or bring several changes of clothing to a tournament so they can shape-shift throughout the day. Pete said he’s tried this, but it doesn’t work for long. Piirimets said that since just his face is enough to get him kicked out, he doesn’t make much of an effort to hide his cell phone anymore. For Pete, it’s the same. And I can see how they’re both distinctive-looking enough to stick out like sore thumbs—Rainer is tall with close-set eyes and thick eyebrows, while Pete has big, glowing eyes that take up much of his squarish face. The first catch instantly halves the viability of a courtsider’s career; the hundredth means it’s almost pointless to continue.

* * *

Not only has enforcement ramped up, but the window of opportunity has shrunk. Chair umpires, who once updated the score relatively leisurely in the gap between points, now race toward the button, and the acceleration has been dramatic enough to threaten the courtsider’s livelihood.

David Lampitt, the managing director of group operations for Sportradar, said reducing lag time for courtsiders to seize upon was a far more effective way of getting them out of the sport than pursuing a game of hide-and-seek around tournament grounds. “If the data is good enough and fast enough, they should have a very limited opportunity to take advantage,” he said.

Given the control they wield over betting markets, it’s no surprise that chair umpires have been susceptible to corruption themselves. In 2016, The Guardian reported that chair umpires at low-level tournaments on the ITF Pro Circuit had essentially become courtsiders themselves, after taking bribes from betting syndicates.

“The four umpires who have been suspended are alleged to have deliberately delayed the inputting of these scores, thereby giving gamblers, some of whom may have been present at courtside, 30 seconds to a minute of advance warning before the betting odds moved in response to the updated score,” Sean Ingle reported. “In some cases, the umpires were texting the score directly to gamblers before it had been officially updated.”

One top chair umpire whom I spoke to who did not wish to be named said umpires sometimes feel a higher standard is placed on that task than actually officiating the match well.

“There is an imperative to not just be fast now, but accurate as well,” the umpire said of inputting the score after each point. “A strange directive, really: Please put in the score as fast as you can, but don’t make any mistakes while doing it. Scoring errors are the bane of the betting companies who pay for the data we input. Umpires have actually been sent home from Challenger events, for example, for making too many scoring errors in a match.

“It’s totally warped—you’d have to fuck up pretty badly with the rules to get sent home, but whatever you do, don’t input the score wrongly too many times.”

The umpire said that the tension this directive caused was another example of betting pressures having a corrosive impact on the people on court.

“Ever since gambling entered tennis, things have changed on so many levels,” the umpire said. “All the social-media vitriol players are subjected to is 99 percent gambling-related, and this extra hidden pressure on us is the same.”

That attitude—that gambling has an overall corrosive effect on tennis—is commonly held among players and many tour employees, who feel only the negative outcomes of it, primarily vicious social-media messages from aggrieved bettors who lost when the players lost. They also see hypocrisy in tournaments and federations accepting bookmakers as sponsors while prohibiting players to do the same. Others see gambling as a natural part of sports, either as a fun sidebar enhancing the competition or the raison d’être for the competition even being played. The whole point of a tennis match taking place, especially at the lower levels, is to bet on it. The players are simply human substitutes for the dice on a craps table.

Further coloring the lens vis-à-vis gambling are the widely varying attitudes toward it in the countries where courtsiding occurs. With sports betting only made legal recently in the United States, many Americans see sports betting as a seedy, underground vice.

In Great Britain, however, sports betting shops are a mundane, ubiquitous part of the urban landscape. As with many other businesses, more transactions are being completed online now, but there are over 9,000 walk-in betting establishments in the country; the bookmaker William Hill has more than 2,300 alone. To put that into context, that’s more William Hills per capita in Great Britain than there are locations of CVS or Walgreens per capita in the United States, and just slightly fewer than there are Starbucks locations. Millions of Americans can execute a complicated latte order, but few can name even a single bookmaker.

* * *

As courtsiders will quickly point out, traditional bookmakers have little to do with their craft. The gambling operations for which courtsiders work trade rarely with those major betting houses, but primarily on the betting exchange Betfair, which operates more like a stock market than a casino. Bettors set their own odds and take bets against each other, not the house.

“There’s no bookmaker telling you what odds you have to take,” Betfair’s website explains. “Think of it as like two mates in a pub with opposing views on a game and having a bet. Betfair works like an impartial barman in the pub who holds the money until he gives it to the winner.”

One party sets odds and a price that another party agrees to, and the bet is on (Betfair usually keeps 5 percent). While there are more casual users, the professional gamblers will often continuously place and change their odds and wagers and stakes as the match progresses and their algorithms adjust their forecasts.

Often, courtsider-led betting syndicates will match up against each other, putting both the fast fingers at the tournament and their respective algorithms to a head-to-head test. It’s common for courtsiders to recognize one another from across the court at a match. At bigger tournaments, they may spot a dozen or more such familiar faces in the crowd. Brad Hutchins estimated that there have been as many as 50 courtsiders working simultaneously inside the main stadium at a Grand Slam; another thought the number could be nearly twice as high.

Those numbers have dwindled now.

* * *

Despite his battle-testedness, Pete has clearly been psyched out by a recent string of setbacks. He had been in New York since the tournament started, but said he didn’t bother attending any of the first five days of it. Even though he’s never been caught at the US Open, and has thus never been given a 20-year ban like the one Piirimets carries, Pete said he won’t risk getting caught there this week and doesn’t plan on going to the tournament this year.

“I don’t want to give them the pleasure,” he said of the spotters. “I know they would get good pleasure out of it.”

It’s a bizarre moment for Pete to suddenly decide to give up, especially after he’d already flown to New York. Why would it suddenly be too unbearable to be caught for roughly the hundredth time? But it’s clear that Piirimets’ arrest has rattled them both.

When news first broke back home that an unnamed Estonian man had been arrested, it was quickly covered across all media in the country of 1.3 million people. As often happens when a courtsiding story hits media, the courtsiders were frustrated by what they saw as a mischaracterization of their work. The Estonian reports, they said, made courtsiding sound like a seedy form of corruption.

“Estonia is quite small, and my phone has been ringing since it happened,” Pete said. “‘Are you okay? Is it you?’ My mom had been crying her eyes out the entire morning. And this is what I’m saying, that I’ve always told her as well: We’re not criminals.”

Though they remain steadfast, the arrest feels like a tipping point. Further, Pete has a wife and a 6-year-old daughter back home.

“Obviously she doesn’t like it, but we’ve been together for a long time now,” Pete said of his wife. “I just go away for a week, but then I come back. Sometimes early on she would come for a week, but she doesn’t like traveling.”

What keeps him going?

“Well, the money, obviously,” Pete said.

But with the margin shrinking and their ejections mounting, the money Pete said they make is now fairly meager, claiming to net only $20,000 to $30,000 a year, roughly.

“And we don’t make any money when we get kicked out in the first match on a Monday, and then we have expenses,” Piirimets added.

Though no overarching data has been made available on the trends in courtsiding, there is a sense on both sides of the battle that courtsiders are losing the war. Their conditions are worsening; in New York, the pair were staying at a Best Western in Queens, near noisy subway tracks. Their patience with the status quo was clearly wearing thin.

“They’re laughing at us, and I don’t like it,” Pete said of the spotters. “And I’m not saying that what we do is perfectly normal, and we should keep doing it for the next 10 years. But their money is buying everything right now, and maybe I should have invested in something different.”

“But you don’t have to feel sorry for us,” Pete added, before ridiculing the opposition forces.

“The spotters make more than we do: $1,500 a week! The spotters are probably making more than chair umpires, which is quite funny, I think. It’s not hard work, is it?”

The only reason Pete wanted to participate in this story, he said, was to draw attention to what he sees as hypocrisy on the other side, to “shake their little paradise tree.”

* * *

As the breed continues to die off, what will become of the few courtsiders who have hung on isn’t clear.

I haven’t heard from Rainer since we parted ways outside the Applebee’s, so I don’t know whether he’s continued courtsiding after his arrest or not (or if he flew back to New York for his court appearance in October, which I doubt he would have).

Pete said he hadn’t completely given up courtsiding when I last heard from him, but he’d also found a new side hustle back home: selling new and used golf equipment, and renting three indoor golfing screens for year-round use in the cold country. Only 2,000 Estonians currently play golf, he said, but he expects that figure to triple.

“They are working hard to pump it up to 6,000 in the next three, four years,” Pete said. “So, all those new players will need to buy new equipment somewhere.”

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